Manufacture of soap



Oct. 11, 1950 R. v. OWEN, 2.525.936

MANUFACTURE OF SOAP 5 Sheets-Sheet 1 Filed Jan. 8, 1948 FIGS FIG. I.

INVENTOR.

RONALD VINCENT OWEN H/S A TTORNEYJ.

Oct. 17,1950 R. v. OWEN MANUFACTURE OF SOAP 5 Sheets-Sheet 2 Filed Jan. 8, 1948 INVENTOR. RONALD VINCENT OWEN HIS ATTOR/VfYS.

Oct; 17, 1950 R. v. OWEN 2,525,936

MANUFACTURE OF SOAP Filed Jan. 8, 1948 5 Sheets-Sheet 5 INVENTOR. RONALD VINCENT OWEN BY W? 6w:

Patented Oct. 17, 1950 MANUFACTURE OF SOAP Ronald Vincent Owen, Sale, England, assignor to Lever Brothers Company, Cambridge, Mass., a

corporation of Maine Application January 8, 1948, Serial No. 1,159 In Great Britain January 20, 1947 The present invention relates to improvements in the manufacture of soap.

In the conventional process of soapmaking fats are first saponified by chemical reaction with aqueous alkali to give a product which is a mixture of soap, water and glycerine. The soap is grained out from this product by the addition of salt or brine and the lye which separates from the soap and contains part of the glycerine is run off after settling. Most of the glycerine remaim ing in the grained soap is removed by successive treatments with brine or lye of the appropriate salt content. The soap is next fitted by being boiled with that quantity of electrolyte, such as salt and/or caustic soda, necessary to establish such phase conditions in the molten fitted soap produced that, on allowing the molten fitted soap to settle, it will separate into an upper layer of molten neat soap and a lower layer of "nigre with perhaps a layer of middle soap between them. For the purpose of' this specification, the term nigre will be used hereunder to define collectively all the products of settling. other than moltenneat soap; that" is to say middle soap and any aqueous lye which may settle from the nigre as well as the product known specifically-as nigre in commercial soap making processesdlllolten neat'soap contains in general 60to 65% total fatty matter, less than 1% of electrolyte and alittle glycerine. "The nigre'layer is-a considerably more aqueous layer of soap containing a higher concentration of electrolyte than the molten neat soap layerand also contains glycerine and impurities. The composition of the molten neat soap layer in'settled molten fitted soap is fairlyconstant, andsuper;

,fluous aqueous liquor from such" fitted soap products into the" above-mentioned layers of nigre'and moltenneat soap. For the purposes 5 Claims. (Cl. 260-418) settled from the molten neat soap to the desired extent. The layer of molten neat soap is usually skimmedoffthe vessel and then passed to the next stages of the soapmaking process. Since the moltenneat soap layer is numerous feet in depth, a settling time often extending up to 2 to 4 days isrequired in order to allow the nigre substantially to separate from it. Initially the nigre settles out comparatively rapidly, after which the rate of settling diminishes until finally settling becomes very slow. This diminution in settling rate is thought to be due to variations in the relative'densities and viscosities of the mixed phases during settling, for in the initial stages of Oneobject of the present invention is to provide a continuous method of separating the nigre and -molten neatsoap from moltenfitted soap and ,to effect thereby a reduction in the time required for complete separation. Another ob-,- ject of the present invention is ;to provide a continuous method of fitting soap and of separating nigre and molten neat soap from the resultant molten fitted soap.

According to the present invention, there is provided a continuous method of separating nigre and molten neat soap from molten fitted soap which comprises maintaining a quiescent fiow of said molten fitted soap so as to allow the nigre to-separate out by'gravity.

of this specification, the term molten fitted soap will be used to define the products of the fitting stage comprising a mixture of nigre and molten neat soap.

In the conventional soapmaking processes, the settling of molten fitted soap is carried out idiscontinuously, batchesof molten fitted soap being allowed to stand in vessels having a. comparatively large capacity (usually the same vessels in which the soap was fitted) until the nigre has 'In my co-pending application, Serial No. 722,793,-filed January 18, 1947, there is described a continuous method of washing soap to remove glycerine therefrom. The "product of this or any other soapmaking process, capable of providing a continuous stream of molten washed soap, may be continuously fitted by adding an appropriate quantity of electrolyte solution to the stream and agitating the resultant mixture to bring about the desired quality of fit. The resultant continu- .;ous stream of molten fitted soap is then continuously settled, the separation of the phases being brought about by conducting the stream of molten fitted soap formed to an arrangement therefore, there is provided a process of soapmaking which includes the steps of continuously fitting washed soap by adding requisite quantities of aqueous electrolyte to said soap and agitating the ingredients to produce a mixture of the phases of molten neat soap and nigres in the form of a continuous stream of molten fitted soap, continuously separating the nigre and molten neat soap from said molten fitted soap by maintaining a quiescent fiow of said molten fitted soap so as to allow the nigre to separate out by gravity and withdrawing settled neat soap.

Preferably in any aspect of the invention the quiescent flow of molten fitted soap is substantially horizontal, though flows in directions inclined to the horizontal come within the scope of the invention. In the case, however, where the fiow has a vertical component of movement, care must be taken that this is not so large as to interfere with the downward movement of settling nigre.

The invention also provides apparatus for carrying out the above methods.

In a preferred arrangement, the stream of molten fitted soap is divided equally amongst a number of shallow settling trays arranged vertically one on top of the other to economise in space and to minimise heat loss. In each of these trays, a substantially horizontal and quiescent flow of molten fitted soap is maintained. The nigre layer settling out from each flow of molten fitted soap is withdrawn from the underside of each tray whilst the molten neat soap above this nigre layer fiows to the end of the tray where it is withdrawn. In such arrangements, owing to the shallowness of the layers, nigre separates out from a given volume of fitted soap in a time which is comparatively much shorter than that which has to be allowed in a batch process. Furthermore, the travs may be enclosed and lagged, hence the drop in temperature and consequent rise in viscosity which retards settling is less than with the batch process.

The invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic representation of an arrangement for adding aqueous electrolytes to molten washed soap for continuous fitting;

Figure 2 is a diagrammatic representation of an arrangement for agitating the mixture of aqueous electrolyte and molten washed soap for continuous fitting;

Figure 3 shows an alternative form of the arrangement of Figure 2;

Figure 4 shows a side view elevation of the vertical arrangement of troughs, in the preferred arrangement for carrying out continuous settling;

Figure 5 shows a plan view of Figure 4;

Figure 6 shows an end elevation of the arrangement of troughs looking in the direction of arrow X in the Figures 4 and 5;

Figure 7 shows an end elevation of the arrangement of troughs looking in the direction of arrow Y in Figures 4 and 5;

Figure 8 shows a diagrammatic representation of an alternative arrangement for carrying out continuous settling; and

Figure 9 shows a diagrammatic representation of a further alternative arrangement for carrying out continuous settling.

For the purpose of the present invention, it is necessary to have available a continuous stream of molten washed soap. Such a stream may be made available from conventional batch methods of washing soap by arranging for a number of washing pans to be used in rotation, one pan providing the stream of washed soap while the washing process is proceeding in the others.

Alternatively, as mentioned above, a continuous stream of molten fitted soap may be conveniently obtained from a continuous washing process, such as that disclosed in co-pending application, Serial No. 722,793, by adding the requisite small flow of caustic liquor and brine or water to bring about the desired quality of fit to the continuous stream of washed soap obtained from the process. Taps for effecting this addition may be located directly above the overflow trough for washed soap in any of the forms of apparatus described in the specification of that application.

Referring now to the drawings, an arrangement for adding the necessary ingredients for fitting a stream of molten washed soap from any suitable supply is shown in Fig. 1. In this figure, a small receiving vessel is fed with washed soap from the pipe 46 fitted with a valve 41. The necessary electrolytic ingredients are supplied into the vessel 45 by the brine, caustic liquor and water pipes 48, 49 and 50, respectively, which are provided with valves 5 I, 52 and 53, respectively, and which may be connected to flow rate control devices. The level of the ingredients in the vessel 45 is governed by the ball valve 54 (or other suitable device), which is used to control the aperture of the valve 55 in the run-off pipe 56. This control may also be used to operate the steam valve 59 of the steam injectors, shown in Figs. 2 and 3, which serve to supply the necessary means of agitation for the fitting operation.

Other methods for adding the necessary ingredients for fitting to a stream of molten washed soap are conceivable. For example, the electrolyte liquors may be injected into the supply line of the washed soap.

Figure 2 shows an arrangement for agitating the electrolyte and washed soap mixture to produce molten fitted soap. This mixture is supplied from the pipe 55 into the steam injector 51, which is fed by a steam pipe 58 provided with a valve 59. This injector brings about intimate mixing of the ingredients of the fit. The ingredients of the fit are discharged along the pipe 60 into a closed agitation vessel GI and are further agitated and mixed at boiling point by their turbulent passage to the top of this vessel and over the baflles 62 and 63 before being discharged through pipe 64 to the settling apparatus.

In an alternative arrangement, shown in Fig. 3, the functions of the pipe 56, steam injector 51, steam pipe 58 and valve 59 are similar to those in the arrangement of Fig. 2. An open vessel 65 is, however, provided instead of the closed and bailled vessel 6!. This vessel 65 is of v such size and shape as to permit a requisite peof the washed soap with the necessary aqueous T electrolytes, which brings about phase conditions in the molten fitted soap, which are such that on allowing the latter to settle under the proper conditions, it will separate into an upper phase of molten neat soap and a lower phase of nigres.

Figs. 4, 5, 6 and 7 show various aspects of the preferred arrangement for carrying out continuous settling, to which molten fitted soap obtained from any of the above-mentioned arrangements may be conducted either directly or through an intermediate storing and conditioning vessel, if such a vessel is required.

The construction of the apparatus of Figs. 4, 5, 6 and 7 will be described followed by its mode of operation.

Referring to Figs. 4, 5, 6 and '7, six trays I with sloping bottoms are mounted one above the other. Each tray is divided into four equal compartments 2 by three guides 3 running the whole length of a tray (Fig. A horizontal distributing trough 4 with a weir 5 are located at the bottom of the deep end of each tray, and a series of funnels 6 on a common draining pipe 'I is provided for emptying the space between the weir 5 and the end wall of the tray through lead off pipes 8 controlled by valves 9. Similarly the contents of the remaining space in the tray may be discharged into the same funnel and draining pipe by lead off pipes l9 controlled by valves l l.

The draining pipe I terminates in two branch pipes l2 and I3 at its lower end, access to the branch pipes from the draining pipe being controlled by a three way valve l4.

Equally spaced pipes l5 connect the distributing trough 4 to two horizontal manifolds IE on the outside of each tray as shown in Figs. 4, 5 and '7. Short vertical pipes ll connect each of the two manifolds It to a third horizontal manifold H! which in turn is connected to one of a series of six funnels l9 by stems 20 (Fig. '7). These six funnels are arranged in a horizontal row parallel to the end wall of the top trough. A feed tank 2| carrying a distributor 22 and feed pipe 23 projects over the deep end of the tray and is fitted with a weir 24 and chute 25 so that the chute discharges into the-row of funnelsl9. This feed tank has a sluice gate 26 in its bottom so that the contents of the tank can be discharged into the top tray if desired.

The shallow end of the tray is closed by a weir 21 and carries a chute 28fitted with guides 29,

illustrated in the case of the top tray in Fig. 5. The chute 28 terminates in a sluice gate 30 discharging into a spout 3| which in turn discharges into one of a series of six funnels 32 on a common drain pipe 33;

The operation of the apparatus is as follows:

Valves 9 and l l are closed and valve l4 opened to branch pipe 12. Molten fitted soap is con ducted in a continuous stream to feed tank 2i.

When the tank 2| is full, the molten fitted soap fiows over the weir 24 down the chute 25 into the funnels [1. The arrangement of funnels l'l, stems 20, manifolds l6 and I8, pipes 1 l5 and I! and distributing troughs 4 serves to provide an even distribution of molten fitted soap the distributing trough 4. The space between the weir 5 and the end wall of the tray. fills up and the molten fitted soap fiows over the weir 5 to form a pool at the base of the weir within the main body of the tray. The molten fitted soap spreads in a quiescent manner until its extremity reaches the base of weir 21 at the shallow end of the tray when the tray then begins to fill. Nig re separates out under gravity from the quiescently spreading molten fitted soap to form a lower layer whilst molten'neat soap remains as a layer on the surface. The surface of liquid in the tray rises gradually until the weir 21 becomes submerged, at which stage, the molten neat soap forming the surface layer begins to flow over the weir 21 and out of the tray into chute 29. A substantially horizontal and quiescent fiow of molten fitted soap through each tray is thus created.

The sloping bottom of the tray enables the nigre which settles out as a lower layer to run counter-current to the flow towards the deep end of the tray whenever the valves II are opened. This nigre is prevented from mingling with incoming flow of molten fitted soap by the weir 5 and can be withdrawn from the tray through leadoif pipes 10, funnels 6, draining pipe 1 and branch l2 by opening, the valves l I either manually from time to time or at automatically controlled intervals by mechanical or other suitable means.

- The rate of nigre withdrawn must not be so rapid or violent as to disturb the even flow of the travelling surface layer of molten fitted soap. Hence the height of the weir 5 with respect to the weir 21 and to the bottom of the tray is arranged to provide for a buffer layer of intermingled soap and nigre between the upper layer of molten fitted soap and lower layer of settled nigres.

When a tray is full and the weir 21 is submerged, the sluice gate 30 at the shallow end is raised. This gate may be adjusted to narrow the effective length of the weir, thereby increasing the depth of molten neat soap flowing over the weir. This minimizes any drag which may be caused by any viscous skin formed on the liquid surface of the soap by local cooling as it flows out of the tray through the spout 3|, funnel 32 and draining pipe 33. The preferred long and narrow shape of the trays also assist in creating of a greater depth of soap flowing overthe weir 21 than is possible with other constructions for the same rate of throughput.

The formation of this undesirable viscous skin I may be reduced by completely enclosing the arrangement of troughs and also bylagging the troughs to prevent cooling of the surface of the liquid ineach trough. I

If it is desired to empty the apparatus, any nigre forming a bottom layer in each trough is first withdrawn through pipe l2. The contents of feed tank 2| are also discharged into the top trough by opening the sluice gate 26 and the space between the weir *5 and the end of wall of each trough is emptied by opening the valves 9. Valve I4 is then opened to branch pipe. l3 and the contents of the troughs are allowed to drain through the draining pipe I and branch pipe 13.

neat soap of a desired quality may be obtained from considerations of the rates at which nigres settle from molten fitted soap in conventional batch processes. The sloping bottomof each tray not only facilitates nigre collection and withdrawal but also conforms to, diminishing rates 7 of nigre settling as the molten fitted soap traverses the tray. A minimum of depth of l or 2 feet is required at the deeper end whilst a few inches sufiiccs at the shallower end. The effective volume of a tray, that is, the product of the surface area and the mean depth of the travelling surface layer is adjusted to provide the necessary time of settling for a given output of molten neat soap. A combination of six trays each 12 ft. long and 4 ft. wide and of a depth of the order mentioned above, is generally capable of settling one ton of good quality molten neat soap every hour. The quality of the resultant molten neat soap may be controlled by varying the number of trays employed or the rate of throughput per tray.

Variations of the particular arrangement described above are possible for carrying out the method of the invention. On such variation, utilizing as a shallow tray the bottom of an ordinary soap boiling pan, is shown diagrammatically in section in Fig. 8. Referring to Fig. 8 the soap boiling pan 34 is provided with an inlet pipe 35 controlled by a valve 35 and an outlet pipe 3'1 controlled by a valve 38. Inlet pipe 35 communicates with a distributor 39 at the bottom of a distributing trough 40 secured along the inner wall of the pan as shown in Fig. 8, whilst outlet pipe 31 communicates directly with a similar trough ti also secured along the inner wall of the pan, but at a higher level and on the opposite side of the pan to trough 49. A draining pipe 42 controlled by a valve 43 is fitted to the bottom of the pan whilst a bafile 44 is located directly in front of trough 40.

At the start of operations, valve i3 is closed and valves 36 and 38 open. A continuous stream of molten fitted soap is fed to'the pan 34 through pipe 33 and distributor 39. Trough 40 fills up and distributor 39 becomes submerged. When trough is full, the molten fitted soap fiows on to the sloping bottom of the pan and collects in a pool above pipe 42. This molten fitted soap spreads in a quiescent manner and nigre settles out under gravity to form a lower layer with a layer of molten neat soap above it. The level of liquid in the trough gradually rises and first trough 4n and then the vertical side of trough 4| becomes submerged. As soon the level of the liquid reaches the bottom of the baffle 44, the latter serves to help to distribute said liquid equally throughout the pan, and to keep the travelling layer of soap under a heat insulating skin of soap which forms on the surface. When the vertical side of trough 4! is submerged, molten neat soap flows into trough Ill and out of the pan through pipe 38. A substantially horizontal and quiescent flow of molten fitted soap is thus created in the soap boiling pan from which nigre settles out under gravity. As in the case of the abovedescribed preferred arrangement, nigre may be withdrawn from the underside of the flow through draining pipe 42, by opening valve 43 either manually from time to time or at automatically controlled intervals by mechanical or other suitable means. A vertical series of such trays may be built up within the soap pan in order to obtain a maximum output from its total volume.

Figure 9 shows yet another variation wherein a vessel 6'! contains a vertical series of narrowly spaced, slightly inclining shelves 68 with end baffles 69 and T4. The shallow spaces between these shelves are designed to permit the settling of the molten fitted soap, which is divided into an equal number of quiescent flowing layers and is introduced via the pipes l l, the distributors l2, and is supplied from the funnels '33. This feeding arrangement is similar to the manifold and funnel equipment as shown in Figs. 4, 5 and '7. The baffle plates 74 help to spread the emerging molten fitted soap laterally across the trays and to prevent local disturbance. The trays may be provided with runner guides similar to theguides 3 in Fig. 5.

The settled nigre passes through the narrow apertures '10 below the bafiles 14 into the end column 15 of the vessel 61 to be withdrawn through the pipe 76 and the valve IT. The separated molten neat soap passes through the narrow apertures 85 above the bafiles 59 into the end column 18 to rise over the weir 19 int0 the column 80 to be withdrawn through the pipe 8| and the funnel 32. The pipe 83 and the valve 84 are used for draining the column 1'8 when required. Sample taps or recorders at the points 81 are used to estimate the soap as a result of which estimation the rate of nigre withdrawal from the column 15 is controlled; automatic control between the points 8'! and the valve 1? may be supplied. The methods of starting up, controlling, and withdrawing the settled ingredients are similar to those for the previously described arrangements.

The above described settling arrangements and other conceivable modifications of them provide for a quiescent layer of molten fitted soap moving slowly and evenly in a horizontal direction or a slightly upward direction (Fig. 9), that is, in a direction giving least interference with the downward movement of the settling nigre. The settling vessels and trays are so chosen that their shapes and dimensions provide for adequate space time factors in accordance with the rates at which nigres settle out from molten fitted soap. The process according to the invention is particularly useful in that it can be linked with continuous forms of the preceding soapmaking operations. The invention also results in a saving of time and heat as well as volume of apparatus for a given output as compared with the batch process and has the advantage of requiring less power, maintenance and other costs when compared with more mechanical fitting and settling processes that are known.

It is to be understood that the modifications suggested herein are but a few of the many that will suggest themselves to those skilled in the art upon reading this description. All such modifications are intended to be included within the scope of this invention as defined in the appended claims.

I claim:

1. A continuous process of separating nigre and neat soap from molten fitted soap in the absence of centrifuging which comprises maintaining a continuous and substantially horizontal quiescent flow of said fitted soap in a shallow stream forming, by action of gravity, an upper phase of neat soap and a lower phase of nigre, continuously and selectively withdrawin the neat soap from said upper phase, and selectively withdrawing the nigre from said lower phase.

2. A continuous process of separating nigre and neat soap from molten fitted soap in the absence of centrifuging which comprises forming a shallow continuously moving, substantially horizontal quiescent stream of said fitted soap, whereby molten neat soap rises in said stream to form an upper phase and nigre descends by action of and selectively withdrawing the nigre from saidlower phase.

, 3. In the manufacture of neat soap in the ab-, sence of centrifuging, the steps comprising forming a shallow continuously moving, substantially horizontal quiescent stream of fitted soap, where by molten neat soap rises in said stream to form an upper phase and nigre descends by action of gravity to form a lower phase, selectively withdrawing the neat soap from said upper phase, and selectively Withdrawing the nigre from said lower phase.

4. A continuous process of separating nigre and neat soap from molten fitted soap in the absence of centrifuging which comprises forming a shallow continuously moving, substantially horizontal quiescent stream of said fitted soap, allowing said stream to separate by action of gravity without further treatment into an upper phase of neat soap and a lower phase of nigre,

continuously and selectively withdrawing the neat soap from said upper phase, and selectively withdrawing the nigre from said lower phase.

5. In the manufacture of neat soap in the absence of centrifuging, the steps which comprise forming a shallow continuously moving, substan- .tially horizontal quiescent stream of fitted soap,

allowing said stream to separate by action of gravity without further treatment into an upper phase of neat soap and a lower phase of nigr'e, continuously and selectively withdrawing the neat soap from said upper phase, and selectively withdrawing the nigre from said lower phase.

RONALD VINCENT OWEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,300,749 Scott Nov, 3, 1942 2,300,750 Scott Nov. 3, 1942 2,411,468 Sender Nov. 19, 1946 2,411,469 Sender Nov. 19, 1946 FOREIGN PATENTS Number Country Date 14,750 Great Britain Apr. 21, 1910 OTHER, REFERENCES Kirschenbauer: Fats and Oils (1944), Reinhold Publishing Co., pages 71 to 74. 

1. A CONTINUOUS PROCESS OF SEPARATING NIGRE AND NEAT SOAP FROM MOLTEN FITTED SOAP IN THE ABSENCE OF CENTRIFUGING WHICH COMPRISES MAINTAINING A CONTINUOUS AND SUBSTANTIALLY HORIZONTAL QUIESCENT FLOW OF AID FITTED SOAP IN A SHALLOW STREAM FORMING, BY ACTION OF GRAVITY, AN UPPER PHASE OF NEAT SOAP AND A LOWER PHASE OF NIGRE, CONTINUOUSLY AND 